Cobble removal from push benches



Dec. 4, 1934. c. w. LITTLER 1,982,677

COBBLE REMOVAL FROM PU SH BENCHES Filed May 24, 1932 2 SheetsShet l l\\Y L. INVENTOR Dec. 4, 1934.

c. w. LITTL ER COBBLE REMOVAL FROM PUSH BENCHES Filed May 24, 1952 2Sheets-Sheet 2 7 R O. T N .E 7 M N Patented Dec. 4, 1934 1,982,677COBBLE REMOVAL FROM PUSH BENCHES CarlW. Littler, Pittsburgh, Pa,assignor to Jones & Laughlin Steel Cor pora'tion, Pittsburgh, Pa,

a corporation of Pennsylvania Application May 24, 1932, Serial No.613,191

16 Claims.

This invention relates to the manufacture of hollow articles by the pushbench process, and more particularly to the removal of cobbles from apush bench. It relates still more particularly to certainmethods andapparatus for the removal of cobbles from a push bench.

In the .push bench process of manufacturing hollowarticles a so-calledbottle is provided which is hollow throughout the greater portion of itslengthand is open at one end and closed at the other end. This bottle isplaced over the nose of a mandrel and pushed through a series of dies tothin and elongate the .bottleinto a hollow blank.

The mandrel is pushed through the dies by a A mandrel pusher bar whichisconnected with the mandrel at the rear end of the latter, suitablemechanism being provided for moving the mandrel pusher bar eitherforwardly or rearwardly at will. Normally the mandrel carrying thebottle about its nose is pushed by the mandrel pusher bar through thedies until the bottle has been thinned and elongated to the desiredextent and until the rear end of the mandrel has emergedfrom. the lastdie. The mandrel, with the blank still on it, is thendisconnected fromthe mandrel pusher bar and transferred to stripping mechanism where theblank is stripped from the mandrel, and theclosed forward endof theblank is then shearedoif and the blank subjected to further finishingoperations, if desired. The

mandrel is reused with another bottle. After disconnection of themandrel the mandrel pusher bar is withdrawn or moved rearwardly to itsinitial position at the entrance end of the push bench where it isprovided with another mandrel and the operation'is repeated.

During the forward movement of the mandrel and blank through the diesthe metal of the blank is subjected to extremely heavy pressures createdbetween the dies and the mandrel and the friction between the movingblank and the dies is of course very great. The pressure of the mandrelon the closed forward end of the blank is largely reliedon-to carry theblank through the dies. Thus, the metal of the blank adjacent'theperiphery of the nose of the mandrel is subjected to tremendousstrain because it is relied on to insure continued forward movement ofthe entire blank with the mandrel in opposition tort-he frictionalresistance of the dies. 'As is only to be expected, the metal at suchportion of the blank sometimes fails and the nose of the blank tearsoff, leaving the 'bodyof the blank in engagement with the dies, Thefrictional resistance between-the outer surface of the mandrel and theinner surface of the blank is small compared with the resistance offeredby the dies, and consequently when the mandrel punches through a blankthe body of the blank remains fhung up in the dies, forming a cobble,while the mandrel slides through the cobble, carrying thenose of theblank with it.

Due to the heat of the blank and the high pressures created in the pushbench, not only the blank but also the dies and the surroundingsupporting structure are at a high temperature so that it is verydifiicult for workmen to work on the cobble toremove it, and whereordinary methods of removal are used the men are forced to work underadverse conditions and the operationof the push bench is interrupted fora considerable time. The investment in a single push bench mayrun intoseveral hundred thousand dollars, and in some cases a million dollars ormore, so that every idle minute may be very expensive. I I provide forthe rapid. removal of a cobble .without the necessity of manuallyworking on the cobble when it isfhung up in the dies and without thenecessity of waiting for it to cool off. I Withdraw the cobble towardthe entrance .end "of the push bench, and I. preferably use either themandrel or the mandrel pusher bar for this purpose. I move either themandrel or the mandrel pusher bar, or both, backwardly while within thecobble and cause the same to carry the cobble therewith whereby toremove it at the entrance end of the push bench. Longitudinallyremovable dies may or may not be used, but when used facilitate removalof the cobble, as will be described. Means may. be provided extendingtransversely of the mandrel or mandrel pusher bar for engaging thecobble, preferably at its forward end, whereby upon backward movement ofthe mandrel or mandrel pusher bar the cobble may be positively movedtoward the entrance end of the push bench.

Other objects and advantages of the invention will become apparent asthe following description of certain present preferred embodimentsthereof proceeds.

In the accompany drawings I have shown certain present preferredembodiments of the invention, wherein Figures 1A and 1B taken togetherrepresent diagrammatically in plan a push bench, the line .1Z$ at theleft-hand extremity of Figure 1A coinciding with the line x--x' at theright-hand extremity of Figure 1B; 7 ,r 7

Figure 2 is a fragmentary longitudinal crosssectional view through aportion of a push bench illustrating more or less diagrammatically amethod of cobble removal;

Figure 3 is a vertical transverse cross-sectional view through a pushbench; and

Figure 4 is a fragmentary longitudinal crosssectional view through aportion of a push bench illustrating more or less diagrammatically amodified method of cobble removal.

Referring more particularly to the drawings, reference numeral 2designates generally a ring bed provided with a pluralityoflongitudinally spaced grooves 3 in desired ones of which arerespectively positioned die holders l carrying diesv 5. There are guidedfor longitudinal movement through the dies 5 a mandrel 6, shownin chainlines in Figure 1B, and a mandrel pusher bar'l. Suitable drivingmechanism is provided forv driving the mandrel pusher bar in eitherlongitudinal direction as maybe desired, and such driving mechanism mayconveniently comprise rack means, shown diagrammatically at 8 in Figurel, operable by pinion means, shown diagrammatically at 9, driven throughsuitable gearing and a coupling 10 by a motor 11.

When the mandrel pusher bar, disengaged from a mandrel, is in itsextreme right-hand position, viewing Figures 1A and 1B, the forward orleft-hand end of the mandrel pusher bar is spaced from the first orentering die a distance greater than the length of a mandrel. A mandrelis supplied at 12 and is moved laterally into alinement with the mandrelpusher bar. Themandrel pusher bar is provided at its forward end with amandrel socket l3 and the mandrel is provided at its rearward end with aprojection adapted toenter the socket 13 in the mandrel pusher barwhereby to center the mandrel with respect to the mandrel pusher bar,the latter thus being adapted to push the former toward the left throughthe dies in the ring bed. Suitable guides, forming no part of thepresent invention and therefor not shown, are provided for guiding themandrel and mandrel pusher bar.

The respective die holders 4 are maintained in their respective groovesby retaining plates 14.-

fastened to the ring bed by bolts '15. The dies, however, arelongitudinally removable from. the die holders, as each holder has a diereceiving opening tapered forwardly of the bench and each die has atapered periphery so that it is adapted to enter the opening in itsholder from the rearward end of the push bench and to be held therein byfriction during forward movement of the mandrel, mandrelbar and blank.Thus in the normal operation of the push bench the tendency is to pushthe dies more firmly into their tapered seats in the die holders,although, as will be readily appreciated, the dies may be removed fromtheir respective holders by rearward pressure.

Sometimes, for reasons above stated or for other reasons, the mandrelwill punch through the closed forward end of the blank, leaving the bodyof the blank hung up in the dies. Such a blank or cobble is shown at 16.i The place where the forward end of the blank was torn away isdesignated by the irregular line 17. The cobble is tightly held in thedies, and the mandrel and mandrel pusher bar may be moved forwardlythrough the cobble until the mandrel has cleared the last die, whereuponthe mandrel is preferably disengaged from the mandrel pusher bar andremoved. At such time the forward end of the mandrel pusher bar projectssome distance beyond the last die.

A collar 18 is slipped over the end of the mandrel pusher bar and a key19 is inserted against the collar through a transverse opening providedin the mandrel pusher bar so as to prevent the collar from slipping offthe end of the mandrel pusher bar. As shown in Figure 2, the collar ispreferably of such size that it will pass through the last die of thepush bench, or through the last die through which the cobble extends.

As the dies toward the entering end of the push bench are larger, thecollar will then pass through all of the dies between the forward end ofthe cobble and the entering end of the push bench. If the cobble doesnot extend through the last die of the push bench the collar may beconnected with the mandrel bar adjacent the forward end of the cobbleand a collar of as large a size as will pass through the last diethrough which the cobble extends is preferably selected.

The mandrel pusher bar is then moved rearwardly, or toward the right,viewing Figures 1A and 1B, and the collar 18 engages the forward end 17of the cobble and positively forces the cobble toward the right, ortoward the entrance end of the push bench. If the friction between anygiven die 5 and its support 4 is greater than the friction between thecobble and the die, the die will remain in place in the support and thecollar 18 will simply push the cobble out through such die, leaving thedie in place. If, however, the friction between the cobble and thedie isgreater than that between the die and its holder, the die will be pushedout of the holder and will move with the cobble. If the smallestdiameter of the tapered opening in the next die holder is larger thanthe greatest diameter of a die carried by the cobble, such die may passthrough or into such opening, or it may strike against the die holderand be loosened on the cobble. Disengagement of a die from its holderdecreases the frictional drag on the cobble, thus facilitating removalof the cobble.

In Figure 4 is shown a modified construction in which'the collar 18,held in place on the mandrel pusher bar by the key 19, has a shoulder 20against which bears a sleeve 21 whose inside diameter is greater thanthe outside diameter of the cobble, the opposite end of the sleevebearing against one of the dies 5. Upon rearward movement of the mandrelpusher bar such die will be disengaged from its support, and as theresistance offered such die by the cobble will ordinarily be greaterthan the resistance offered the cobble by the other dies, the cobblewill move substantially with the mandrel pusher bar toward the enteringend of the push bench. Once the cobble has been loosened its removal iscomparatively easy and the friction between the interior of the cobbleand the exterior of the mandrel pusher bar may be sufficient to effectremoval of the cobble.

Although it is preferred that the mandrel pusher bar shall serve toremove the cobble, the mandrel itself may be used for this purpose ifthe ent preferred embodiments of the invention, it is to be distinctlyunderstood that the same is not limited thereto, but may be otherwisevariously embodied and practiced within the scope of the followingclaims.

I claim:

1. In the removal of a cobble from a push bench, the steps comprisingmoving the mandrel pusher bar backwardly while within the cobble andcausing the mandrel pusher bar to carry the cobble with it whereby toremove the same at the entrance end of the push bench.

2. In the removal of a cobble from a push bench, the steps comprisingmoving the mandrel pusher bar backwardly while Within the cobble andcausing the mandrel pusher bar to carry with it the cobble and the diesin engagement with the cobble whereby to remove the same at the entranceend of the push bench.

3. In the removal of a cobble from a push bench, the steps comprisingmoving the mandrel pusher bar backwardly while within the cobble andcausing the mandrel pusher bar to carry with it the cobble and the diesin engagement with the cobble whereby to remove the same at the entranceend of the push bench, removing the mandrel pusher bar from the cobbleand removing the dies from the cobble.

4. In the removal of a cobble from a push bench, the steps comprisingconnecting with the mandrel pusher bar means for engaging the cobble tocause movement thereof with the mandrel pusher bar upon backwardmovement of the latter while within the cobble, and moving the mandrelpusher bar backwardly whereby to remove the cobble at the entrance endof the push bench.

5. In the removal of a cobble from a push bench, the steps comprisingconnecting with the mandrel pusher bar forwardly of the cobble meansadapted to engage the forward portion ofthe cobble to cause movementthereof with the mandrel pusher bar upon backward movement of the latterwhile within the cobble, and moving the mandrel pusher bar backwardlywhereby to remove the cobble at the entrance end of the push bench.

6. In the removal of a cobble from a push bench, the steps comprisingmoving the mandrel and mandrel pusher bar forwardly through the cobbleuntil the former clears the cobble, detaching the mandrel from themandrel pusher bar, moving the mandrel pusher bar baokwarclly, andcausing the mandrel pusher bar to carry the cobble with it upon suchbackward movement whereby to remove the cobble at the entrance end ofthe push bench.

7. In the removal of a cobble from a push bench, the steps comprisingfastening a collar over the mandrelpusher bar forwardly of the cobble,said collar being adapted to engage the forward portion of the cobble tocause movement thereof with the mandrel pusher bar upon backwardmovement of the latter while within the cobble, and moving the mandrelpusher bar backwardly whereby to remove the cobble at the entrance endof the push bench.

8. In the removal of a cobble from a push bench, the steps comprisingconnecting with the v mandrel pusher bar means for engaging a die andmoving the mandrel pusher bar backwardly whereby to remove at least someof the dies and the cobble at the entrance end of the push bench.

9. Push bench apparatus, comprising a mandrel pusher bar and cobbleremoving means adapted for connection with the mandrel pusher bar toextend transversely thereof.

10. Push bench apparatus, comprising a mandrel, a mandrel push bar, andcobble removing means adapted for connection with the mandrel pusher barnear its forward end to extend transversely thereof.

11. Push bench apparatus, comprising amandrel pusher bar and a cobbleremoving collar adapted to be fastened over the mandrel pusher bar.

12. Push bench apparatus, comprising a mandrel pusher bar, diesremovable toward the entrance end of the push bench, and cobble removingmeans adapted for connection with the mandrel pusher bar.

13. Push bench apparatus, comprising a mandrel pusher bar, removabledies, and means.

adapted for positive connection with the mandrel pusher bar for engagingand removing at least one of said dies upon longitudinal movement of themandrel pusher bar.

14. Push bench apparatus, comprising a mandrel pusher bar having atransverse opening and means adapted to extend within said opening andto extend outwardly past the lateral surface of the mandrel pusher barto assist in cobble removal.

15. Push bench apparatus, comprising a mandrel pusher bar, a cobbleremoving collar adapted to be placed over the mandrel pusher bar, and akey to maintain said collar in place.

16. A method of removing cobble from a push

